
<html><HEAD>
<LINK REL=STYLESHEET HREF="default.css" TYPE="text/css">
<TITLE>
Specifying an identity column</TITLE>
</HEAD>
<BODY>

<!-- Header -->
<p class="ancestor" align="right"><A HREF="pbugp190.htm">Previous</A>&nbsp;&nbsp;<A HREF="pbugp192.htm" >Next</A>
<!-- End Header -->
<A NAME="BHBCEBDJ"></A><h1>Specifying an identity column</h1>
<A NAME="TI6214"></A><p>Many DBMSs allow you to specify that the value for a column
in a new row is to be automatically assigned by the DBMS. This kind
of column is called an identity column. Different DBMSs provide
different types of identity columns.</p>
<A NAME="TI6215"></A><p> For example, some DBMSs allow you to define autoincrement
columns so that the column for a new row is automatically assigned
a value one greater than that of the previous highest value. You
could use this feature to specify that an order number be automatically
incremented when someone adds a new order:</p>
<br><img src="images/aacu04.gif">
<A NAME="TI6216"></A><p>By specifying an identity column in the Specify Update Properties
dialog box, you tell PowerBuilder to bring back the value of a new
row's identity column after an insert in the DataWindow object so
that users can see it.</p>
<A NAME="TI6217"></A><p>For information about identity columns in
your DBMS, see your DBMS documentation.</p>

